Agricultural harvesters are increasingly equipped with sensors, the output signals of which allow an automatic control of actuators in order to simplify the operation of the harvester for the operator. In addition to operating parameters of the harvester, such as the speeds or torques of driven, crop-conveying elements or crop-processing elements, properties of the crop, such as, e.g., the population density or the level of maturity of the plants or the position of the crop angle, are also determined with sensors in order to automatically adapt the driving speed, the steering angle and/or other operating parameters of the harvester. Sensors of this type usually operate with ultrasound or electromagnetic waves and are mounted at the highest possible point of the harvester, particularly on the roof of the cabin, in order to be able to acquire information on the crop as far in advance as possible and to adapt the operating parameters in due time before the harvester reaches the crop monitored by the sensors (DE 10 2004 039 462 A1 or DE 101 30 665 A1).
In the harvesting of agricultural crops on a field, it is furthermore common practice for a harvester to load a transport vehicle that drives next to the harvester with the harvested crop. A loading container of the transport vehicle that may consist, for example, of a tractor with trailer or a truck is loaded with the harvested crop by a discharging device of the harvester while moving, for example, by an ejection elbow of a field chopper or a tank unloading tube of a combine-harvester. The discharging device is usually mounted on the harvester such that it can be turned about a vertical axis and pivoted between an idle position, in which it is oriented approximately parallel to the longitudinal axis of the harvester, and a working position, in which it extends transverse to the driving direction of the harvester. It may also be possible to vary the height of the ejecting end of the discharging device, as well as the position of an ejection baffle that defines the angle, at which the harvested crop is discharged.
In discharging devices that are normally used on combine-harvesters and cannot be adjusted with respect to their discharging position, the driver of the transport vehicle needs to ensure that the loading container is uniformly and completely filled by gradually positioning different locations of the loading container underneath the discharging device. This task is relatively demanding and exhausting because crop losses due to the crop falling onto the field need to be avoided. It was therefore proposed to equip the transport vehicle with an automatic steering system that is based on positional data transmitted in a wireless fashion (DE 102 24 939 A1). However, the filling level of the loading container is not monitored in this case such that the driver of the harvester still needs to oversee the loading process.
In adjustable discharging devices as they are typically used on field choppers, the position of the discharging device may simply be controlled manually by the driver of the harvester. Automatic controls for the position of the discharging device have been proposed in order to prevent the position control of the discharging device from demanding a significant portion of the driver's attention and resulting in exhausting work for the driver of the harvester. These automatic controls usually comprise a sensor that is arranged on the discharging device and operates with ultrasonic waves or optically (DE 44 03 893 A1, DE 44 26 059 A1).
In the previous arrangement of the sensors for monitoring the crop on the field and/or the transfer process on the harvester, it is considered disadvantageous that said sensors are subjected to vibrations in the harvesting mode due to the driving motion over more or less uneven fields, as well as driven elements of the harvester, such that the acquisition of sufficiently sharp images or accurate data is complicated. In addition, the angle, at which the sensor points at the plant population or the transfer process, is very unfavorable in many instances, particularly if the sensor points relatively far ahead in order to acquire data in advance. This also applies to transfer processes to carts with high walls because the sensor arranged on the discharging device does not detect the crop deposited in the loading container until a relatively high filling level is reached shortly before the loading container is completely filled.
In agricultural engineering, the utilization of remotely piloted aircraft, particularly rotary-wing aircraft, was until now only proposed for monitoring the harvest and protein content of rice plants so as to determine suitable fertilizer quantities (ASABE Paper No. 080038), for inspecting agricultural fields for harmful weeds (DE 20 2008 015 324 U1) or for spraying insecticides (JP 2004 322 836 A1).